Fig. 1. Illustration of the experimental setup for investigation of nonlinear effects in LN microdisks. AFG, arbitrary function generator; PD, photodetector.

Fig. 2. Spectra of nonlinear optical signals and the corresponding transmission of the pump. SHG signals of (a) pulsed and (b) cw pumps, respectively. (c) SFG (red bold line) and SHG signals (blue and black lines) obtained when both cw and pulsed pump lasers were coupled into the LN resonator. (d)–(f) Typical transmission of the pump correspond to (a)–(c), respectively. The wavelengths (input power) of the cw and pulsed lasers were 1547.0 and 1554.6 nm (8.02 and 0.52 mW), respectively.

Fig. 3. Spectra showing nonlinear optical signals for various cw laser wavelengths. The red, blue, and black peaks represent the SFG, SHG of cw laser, and SHG of pulsed laser, respectively. For demonstration, the vertical coordinate for each spectrum is shifted by 10 pW with respect to its preceding one. The wavelength of the pulsed pump was fixed at 1549.7 nm. The input power of the cw and pulsed pumps were set to be 7.81 and 0.51 mW, respectively.

Fig. 4. Dependence of the SFG and SHG intensities on the wavelength of the cw pump and transmission spectra of the cw pump. (a)–(c) Nonlinear signals measured by scanning the wavelength of the cw laser near 1547.0 nm. The wavelength of the pulsed pump was fixed at 1554.6 nm. The input power of the cw and pulsed pumps were set to be 10.92 and 0.71 mW, respectively. (d) Sawtooth voltage for cw laser wavelength scan. Transmission spectra of the cw laser around 1543.0 nm under (e) strong and (f) weak pump, respectively.

Fig. 5. Dependence of nonlinear signals on pump power and the deduced SFG conversion efficiency. (a)–(c) Power of SHG signals of the cw and pulsed lasers and SFG signal with respect to the total pump power. (d) SFG conversion efficiency deduced from (c). The central wavelengths of the cw and ps lasers were set as 1547.0 and 1554.6 nm, respectively. The power ratio of the continuous laser and the pulsed laser was kept as 15.4:1.